Crankset upgrade for a masher

Long story short, on my old hardtail I killed several ISIS bottom brackets and eventually thrashed the splines on my crank. Upgraded to a SLX Hollowtech crankset with external bearings and all was good again.

Now, I have a GF Rumblefish and after less than about 400mi, my crank is creaking to the point I can feel it through my feet. Replaced the press-in bottom bracket with an aftermarket Enduro version but creaks are still there (have new pedals, too), so I have isolated the noise to the splined interface on the crankset (non-drive side). Apparently my 215lb masher riding style is a bit hard on cranksets...any recommendations for a crankset upgrade from the stock Shimano M542? I'll probably try the SLX simply because I had good results on the hardtail. Other suggestions?

Shimano LX, SLX, or XT with external bearing BB. I have been riding them since around 2005 with no issue whatsoever. I usually need to swap bearings sometime about 1 season in. At that point I upgrade to Enduro brand replacements at about $15 and they are good for 1-2 more seasons. If you are a masher odds are you will go through chainrings faster than BB bearings though.